Optimization of ultrasonic extraction of liquiritin by response surface methodology

Dual-frequency ultrasound was used to extract liquiritin from licorice to obtain the optimum process parameters, which were ultrasonic time (A), ethanol volume ratio (B) and ultrasonic duty cycle (C). The prediction model of quadratic polynomial regression equation was obtained by Box-Behnken Design (BBD) and response surface methodology (RSM). The results showed that the optimal process parameters were as follows: The ultrasonic time was 23min, the ethanol volume ratio was 61%, and the ultrasonic duty cycle was 3:2. Under these conditions, the practical extraction rate of liquiritin was 4.142%, which was consistent with the extraction rate predicted of 4.172%.